Halogenated isobutylene-based copolymers having enhanced viscosity and thermoplastic compositions thereof

ABSTRACT

The invention provides a method for increasing the viscosity of halogenated (brominated) elastomeric copolymers of a C 4  to C 7  isomonoolefin (isobutylene) and a para-alkylstryrene (p-methylstyrene) by mixing the copolymer with a silica or clay particulate filler which has been contacted with an aminosilane containing at least one C 1  to C 4  alkoxy group and at least one primary, secondary or tertiary amine group. The resulting elastomer compositions are used to prepare thermoplastic elastomer blend compositions, containing more finely dispersed elastomers which results in compositions having improved mechanical properties.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Application of InternationalApplication No. PCT/US02/13440, filed Apr. 30, 2002, which claims thebenefit of Provisional Application No. 60/296,714, filed Jun. 7, 2001.

FIELD OF THE INVENTION

The invention relates to halogenated copolymers of a C₄ to C₇isomonoolefin and a para-alkylstyrene having enhanced viscosity andthermoplastic compositions containing these copolymers.

BACKGROUND

A thermoplastic elastomer is generally defined as a polymer or blend ofpolymers that can be processed and recycled in the same way as aconventional thermoplastic material, yet has properties and performancesimilar to that of vulcanized rubber at service temperatures. Blends oralloys of plastic and elastomeric rubber have become increasinglyimportant in the production of high performance thermoplasticelastomers, particularly for the replacement of thermoset rubber invarious applications.

Polymer blends which have a combination of both thermoplastic andelastic properties are generally obtained by combining a thermoplasticpolymer with an elastomeric composition in a way such that the elastomeris intimately and uniformly dispersed as a discrete particulate phasewithin a continuous phase of the thermoplastic. Early work withvulcanized compositions is found in U.S. Pat. No. 3,037,954 whichdiscloses static vulcanization as well as the technique of dynamicvulcanization wherein a vulcanizable elastomer is dispersed into aresinous thermoplastic polymer and the elastomer is cured whilecontinuously mixing and shearing the polymer blend. The resultingcomposition is a microgel dispersion of cured elastomer, such as butylrubber, chlorinated butyl rubber, polybutadiene or polyisoprene in anuncured matrix of thermoplastic polymer such as polypropylene.

Depending on the ultimate application, such thermoplastic elastomer(TPE) compositions may comprise one or a mixture of thermoplasticmaterials such as propylene homopolymers and propylene copolymers andlike thermoplastics used in combination with one or a mixture of curedor non-cured elastomers such as ethylene/propylene rubber, EPDM rubber,diolefin rubber, butyl rubber or similar elastomers. TPE compositionsmay also be prepared where the thermoplastic material used is anengineering resin having good high temperature properties, such as apolyamide or a polyester, used in combination with a cured or non-curedelastomer. Examples of such TPE compositions and methods of processingsuch compositions, including methods of dynamic vulcanization, may befound in U.S. Pat. Nos. 4,130,534, 4,130,535, 4,594,390, 5,021,500,5,177,147 and 5,290,886, as well as in WO 92/02582. Other examples ofelastomer compositions including silane-type fillers include EP 1 111004 A1, EP 0 890 602 A1; and WO 99/31178.

Particularly preferred elastomeric polymers useful for preparing TPEcompositions are halogenated random copolymers comprising at least 50mole % of a C₄ to C₇ isomonoolefin (isobutylene) copolymerized with lessthan 50 mole % of para-alkylstyrene (p-methylstyrene). Elastomericcopolymers of this type (referred to as BIMS polymers) and their methodof preparation are disclosed in U.S. Pat. No. 5,162,445. Curable TPEcompositions containing these copolymers are described in U.S. Pat. Nos.5,013,793 and 5,051,477, among others.

TPE compositions are normally prepared by melt mixing or melt processingthe thermoplastic and elastomeric components at temperatures in excessof 150° C. and under high shear mixing conditions (shear rate greaterthan 100 l/sec or sec⁻¹) in order to achieve a fine dispersion of onepolymer system within a matrix of the other polymer system. The finerthe dispersion, the better are the mechanical properties of the TPEproduct.

Due to the flow activation and shear thinning characteristic inherent insuch BIMS polymers, reductions in viscosity values these polymers atincreased temperatures and shear rates encountered during mixing aremuch more pronounced than reductions in viscosity of the thermoplasticcomponent with which the BIMS polymer is blended. However, minimizationof the viscosity differential between the BIMS and thermoplasticcomponents during mixing and/or processing is essential for theprovision of uniform mixing and fine blend morphology that are criticalfor good blend mechanical properties.

SUMMARY OF THE INVENTION

This invention provides a composition comprising a mixture of (a) ahalogenated elastomeric copolymer of a C₄ to C₇ isomonoolefin and apara-alkylstyrene; and (b) at least one silica or clay filler which hasbeen contacted with at least one aminosilane containing at least one C₁to C₄ alkoxy group and at least one primary, secondary or tertiary aminegroup, the particulate filler material present in the composition at alevel of from 0.1 to 100 parts by weight per 100 parts by weight of theelastomeric copolymer.

The invention also provides a thermoplastic polymer compositioncomprising a blend of a thermoplastic polymer and the compositiondescribed above.

The invention further provides a process for increasing the viscosity ofa halogenated elastomeric copolymer of a C₄ to C₇ isomonoolefin and apara-alkylstyrene comprising melt mixing the copolymer with 0.1 to 100parts by weight silica or clay filler which has been contacted with anaminosilane containing at least one C₁ to C₄ alkoxy group and at leastone primary, secondary or tertiary amine group, the parts by weightbased on 100 parts by weight of the copolymer.

Using the aminosilane modified fillers in accordance with thisinvention, the viscosity of BIMS polymers can be raised as the result ofthe introduction of chemical interactions between the amino groups onthe filler surface and halogenated isobutylene polymers. For primary andsecond amine functionalities, covalent bonds can be formed betweenhalogenated isobutylene polymers and the amine modified fillers. Fortertiary amine functionality, ionic associations through quaternizedamines, instead, are promoted.

It is believed that by associating halogenated isobutylene polymerchains onto the filler surface through either chemical bonds or ionicassociations, viscosities of these polymers are enhanced. In addition,chemical absorption of halogenated isobutylene polymer chains onto thefiller surface prevents filler agglomeration and, thus, improves fillerdispersion. During blending with other polymers, the presence of theseinteractions between amine-modified fillers and halogenated isobutylenepolymers also may prevent filler migration to other polymer phases.Although viscosity value of a polymer could be increased simply byincorporating micro or nano fillers without any functionalities, fillermigration is a factor in keeping fillers in the particular polymer phaseduring blending for their intended purpose of viscosity enhancement.Utilizing functionalized fillers thus solves filler transfer problems.

The invention provides a new approach towards viscosity enhancement ofBIMS copolymers such that their viscosity during high shear thermalmixing more closely approaches or matches the viscosity of thermoplasticmaterials with which they are blended, thereby facilitating more uniformmixing and the development of a finer dispersion of one polymer systemwithin the other matrix polymer system.

DETAILED DESCRIPTION OF THE INVENTION

BIMS elastomeric copolymers used as a blend component in the presentinvention are the halogenation product of random copolymers of a C₄ toC₇ isomonoolefin, such as isobutylene, and para-alkylstyrene comonomer,preferably para-methylstyrene containing at least 80%, more preferablyat least 90% by weight of the para isomer, and wherein at least some ofthe alkyl substituent groups present in the styrene monomer unitscontain halogen.

Most useful of such materials are elastomeric copolymers of isobutyleneand para-methylstyrene containing from 0.5 to 20 wt % para-methylstyrenewherein up to 60 mole % of the methyl substituent groups present on thebenzyl ring contain a bromine or chlorine atom, preferably a bromineatom. These copolymers have a substantially homogeneous compositionaldistribution such that at least 95% by weight of the polymer has apara-methylstyrene content within 10% of the average para-methylstyrenecontent of the polymer. They are also characterized by a narrowmolecular weight distribution (Mw/Mn) of less than 5, more preferablyless than 2.5, a preferred viscosity average molecular weight in therange of from 100,000 up to 2,000,000, and a preferred number averagemolecular weight in the range of from 10,000 to 750,000, as determinedby Gel Permeation Chromatography.

The copolymers may be prepared by slurry polymerization of the monomermixture using a Lewis Acid catalyst, followed by halogenation,preferably bromination, in solution in the presence of halogen and aradical initiator such as heat and/or light and/or chemical initiator.

Preferred brominated copolymers generally contain from 0.1 to 5 mole %of bromomethyl groups, most of which is monobromomethyl, with less than0.05 mole % dibromomethyl substituents present in the copolymer. Morepreferred copolymers contain from 0.5 to 1.5 mole % of bromomethylgroups. These polymers, and their method of preparation are moreparticularly disclosed in U.S. Pat. No. 5,162,445. Usefulpoly(isobutylene-co-p-methylstyrene) polymers are brominated polymers(BIMS) sold commercially as EXXPRO™ Elastomers (ExxonMobil ChemicalCompany, Houston Tex.).

Clays and silicas which are useful fillers in accordance with thisinvention include silica, fumed or precipitated silica, kaolin,aluminosilicates, magnesium silicates such as talc, mica such asmuscovite, calcium metasilicate such as wallastonite and other materialswhich are capable of hydrolytic reaction with alkoxy-aminosilanes.Preferred fillers are silica and aluminosilicate based clays. The fillerdesirably has an average particle size in the range of from 0.005 to 25microns (μm), from 0.005 to 25 μm in another embodiment, and from 0.008to 5 μm in yet another embodiment.

In accordance with a desirable embodiment of the invention, the BIMSpolymer useful in the blends of the invention are contacted with atleast one aminosilane compound. In one embodiment, the BIMS andaminosilane are contacted prior to mixing with the at least onethermoplastic. The BIMS/aminosilane (filler) blends thus have improvedviscosity matching with the thermoplastics to be blended with the BIMS.

Aminosilanes used to modify the filler materials are known in the artand generally contain at least one C₁ to C₃ alkoxy group and at leastone primary, secondary or tertiary amine group. These silanes may becharacterized as compounds having in a single molecule one or morehydrolytic groups which in the presence of water generate silanol groups(in the case of silica and aluminosilicates) thereby forming covalentbonds with free surface hydroxyl groups on the filler surface viacondensation reactions. Also present in the aminosilane molecule areamine groups which, in the case of primary and secondary amines, arecapable of forming covalent bonds at the site of benzylic halogen in theBIMS molecules, or non-displacement ionic associations with halogenpresent in the BIMS molecules where the amine group is tertiary.

Suitable aminosilanes include N-(trimethyoxy-silylpropyl)ethylenediamine, N-(trimethoxy-silylpropyl) N′,N′-dimethylene diamine,N-(trimethoxy-silylpropyl) propylene diamine, N-(trimethoxysilylpropyl)diethylene triamine, gamma-aminopropyl triethoxy silane and the like.Most preferred aminosilanes are of the formula (H₂N—R)_(4-n)Si(OR′)_(n)wherein R is C₁ to C₄ alkylene, R¹ is C₁ to C₄ alkyl and n is a wholenumber ranging from 1 to 3. Examples of these preferred aminosilanes aretriethoxy-aminomethyl silane, triethoxyaminopropyl silane,diaminopropyldiethoxy silane, triaminopropyl ethoxy silane and likematerials.

Aminosilane surface modified fillers may contain from 0.1 to 5 wt % ofthe aminosilane, based on the weight of filler, and are prepared bycontacting the filler with the aminosilane (either in neat form or inthe form of an emulsion), drying the coated filler in an oven, fluidizedbed or spray dry process, and screening to the desired particle size.Aminosilane treated clays are commercially available from BurgessPigment Co. under the designation Burgess 2211 and aminosilane treatedsilica is available from the Degussa Company under the Aerosil™designation, such as Aerosil R 504. Other suitable fillers and treatedfillers are described in the BLUE BOOK 274-303 (Don R. Smith, ed.,Lippincott & Peto, 2001).

The amount of modified filler added to the elastomer to achieveviscosity modification may range from 1 to 100 parts phr (per hundredrubber) in one embodiment, from 2 to 60 parts phr in another embodiment,from 3 to 40 phr in yet another embodiment, and from 5 to 35 phr in yetanother embodiment, a desirable embodiment including combination of anyupper phr limit with any lower phr limit described herein.

Thermoplastic Polymers

Thermoplastic polymers suitable for use in the present invention includeany one or more of amorphous, partially crystalline or essentiallytotally crystalline polymers selected from polyolefins, polyamides,polyimides, polyesters, polycarbonates, polysulfones, polylactones,polyacetals, acrylonitrile/butadiene/styrene copolymer resins,polyphenylene oxides, ethylene-carbon monoxide copolymers, polyphenylenesulfides, polystyrene, styrene/acrylonitrile copolymer resins,styrene/maleic anhydride copolymer resins, aromatic polyketones andmixtures thereof.

Polyolefins suitable for use in the compositions of the inventioninclude thermoplastic, at least partially crystalline polyolefinhomopolymers and copolymers, including polymers prepared usingZiegler/Natta type catalysts or metallocene catalysts. They aredesirably prepared from monoolefin monomers having 2 to 6 carbon atoms,such as ethylene, propylene, 1-butene, isobutylene, 1-pentene,copolymers containing these monomers, and the like, with propylene beingthe preferred monomer. As used in the specification and claims, the termpolypropylene includes homopolymers of propylene as well as reactorcopolymers of propylene which can contain 1 to 20 wt % of ethylene or anα-olefin comonomer of 4 to 16 carbon atoms or mixtures thereof. Thepolypropylene can be highly crystalline isotactic or syndiotacticpolypropylene, usually having a narrow range of glass transitiontemperature (Tg). Commercially available polyolefins may be used in thepractice of the invention.

Suitable thermoplastic polyamides (nylons) comprise crystalline orresinous, high molecular weight solid polymers including copolymers andterpolymers having recurring amide units within the polymer chain.Polyamides may be prepared by polymerization of one or more epsilonlactams such as caprolactam, pyrolidione, lauryllactam andaminoundecanoic lactam, or amino acid, or by condensation of dibasicacids and diamines. Both fiber-forming and molding grade nylons aresuitable. Examples of such polyamides are polycaprolactam (nylon 6),polylauryllactam (nylon 12), polyhexamethyleneadipamide(nylon-6,6),polyhexamethyleneazelamide (nylon-6,9), polyhexamethylenesebacamide(nylon 6,10), polyhexamethyleneisophthalamide(nylon-6,IP) and thecondensation product of 11-amino-undecanoic acid (nylon 11).Commercially available thermoplastic polyamides may be advantageouslyused in the practice of this invention, with linear crystallinepolyamides having a softening point or melting point between 160°C.-230° C. being preferred.

Suitable thermoplastic polyesters which may be employed include thepolymer reaction products of one or a mixture of aliphatic or aromaticpolycarboxylic acids esters of anhydrides and one or a mixture of diols.Examples of satisfactory polyesters include poly(trans-1,4-cyclohexylene C2-6 alkane dicarboxylates such aspoly(trans-1,4-cyclohexylene succinate) and poly(trans-1,4-cyclohexylene adipate); poly(cis ortrans-1,4-cyclohexanedimethylene) alkanedicarboxylates such as poly(cis1,4-cyclohexane-di-methylene) oxlate and poly-(cis1,4-cyclohexane-di-methylene) succinate, poly(C2-4 alkyleneterephthalates) such as polyethyleneterephthalate andpolytetramethyleneterephthalate, poly(C2-4 alkylene isophthalates suchas polyethyleneisophthalate and polytetramethylene-isophthalate and likematerials. Preferred polyester are derived from aromatic dicarboxylicacids such as naphthalenic or ophthalmic acids and C2 to C4 diols, suchas polyethylene terephthalate and polybutylene terephthalate. Preferredpolyesters will have a melting point in the range of 160° C. to 260° C.

Poly(phenylene ether) (PPE) thermoplastic engineering resins which maybe used in accordance with this invention are well known, commerciallyavailable materials produced by the oxidative coupling polymerization ofalkyl substituted phenols. They are generally linear polymers having aglass transition temperature in the range of 190° C. to 235° C. Examplesof preferred PPE polymers include poly(2,6-dialkyl-1,4 phenylene ethers)such as poly(2,6 dimethyl-1,4-phenylene ether), poly2-methyl-6-ethyl-1,4-phenylene ether), poly-(2,6-dipropyl-1,4-phenyleneether) and poly(2-ethyl-6-propyl-1,4-phenylene ether). These polymers,their method of preparation and blends with polystyrene are furtherdescribed in U.S. Pat. No. 3,383,435, the complete disclosure of whichis incorporated herein by reference.

Other thermoplastics which may be used include the polycarbonate analogsof the polyesters described above such as segmented poly(etherco-phthalates); polycaprolactone polymers; styrene resins such ascopolymers of styrene with less than 50 mole % of acrylonitrile (SAN)and resinous copolymers of styrene, acrylonitrile and butadiene (ABS);sulfone polymers such as polyphenyl sulfone and like engineering resinsas are known in the art.

The thermoplastic may be added to the BIMS or BIMS/aminosilane blendfrom 10 to 90 wt % based on the total weight of the thermoplastic blend,and from 20 to 80 wt % in another embodiment, and from 30 to 70 wt % inanother embodiment, and from 35 to 65 wt % in yet another embodiment,wherein a desirable wt % range of the thermoplastic in thethermoplastic/BIMS/aminosilane blend can be any combination of any upperwt % limit with any lower wt % limit described herein.

Additives

The compositions of the invention may include plasticizers, curativesand may also include reinforcing and non-reinforcing fillers,antioxidants, stabilizers, rubber processing oil, plasticizers, extenderoils, lubricants, antiblocking agents, anti-static agents, waxes,foaming agents, pigments, flame retardants and other processing aidsknown in the rubber compounding art. Such additives can comprise up to50 wt % of the total composition. Fillers and extenders which can beutilized include conventional inorganics such as calcium carbonate,clays, silica, talc, titanium dioxide, carbon black and the like. Therubber processing oils generally are polybutene, paraffinic, naphthenicor aromatic oils derived from petroleum fractions, but are preferablyparaffinic or polybutenes. The type will be that ordinarily used inconjunction with the specific rubber or rubbers present in thecomposition, and the quantity based on the total rubber content mayrange from zero up to 1-200 parts by weight per hundred rubber (phr).Plasticizers such as trimellitate esters may also be present in thecomposition.

Processing

The BIMS component of the thermoplastic elastomer is generally presentas small, i.e., micro-size, particles within a continuous plasticmatrix, although a co-continuous morphology or a phase inversion is alsopossible depending on the amount of rubber relative to plastic, and thecure system or degree of cure of the rubber. The rubber is desirably atleast partially crosslinked, and preferably is completely or fullycross-linked. The partial or complete crosslinking can be achieved byadding an appropriate rubber curative to the blend of thermoplasticpolymer and rubber and vulcanizing the rubber to the desired degreeunder conventional vulcanizing conditions. However, it is preferred thatthe rubber be crosslinked by the process of dynamic vulcanization. Asused in the specification and claims, the term “dynamic vulcanization”means a vulcanization or curing process for a rubber contained in athermoplastic elastomer composition, wherein the rubber is vulcanizedunder conditions of high shear at a temperature above the melting pointof the component thermoplastic. The rubber is thus simultaneouslycrosslinked and dispersed as fine particles within the matrixthermoplastic, although as noted above other morphologies may alsoexist.

Dynamic vulcanization is effected by contacting or otherwise mixing thethermoplastic elastomer components at elevated temperature inconventional mixing equipment such as roll mills, Banbury mixers,Brabender mixers, continuous mixers, mixing extruders and the like. Theunique characteristic of dynamically cured compositions is that,notwithstanding the fact that the rubber component is partially or fullycured, the compositions can be processed and reprocessed by conventionalplastic processing techniques such as extrusion, injection molding, blowmolding and compression molding. Scrap or flashing can be salvaged andreprocessed.

Those ordinarily skilled in the art will appreciate the appropriatequantities, types of cure systems and vulcanization conditions requiredto carry out the vulcanization of the BIMS rubber. The rubber can bevulcanized using varying amounts of curative, varying temperatures andvarying time of cure in order to obtain the optimum crosslinkingdesired. Any known cure system for the rubber can be used, so long as itis suitable under the vulcanization conditions with the specific BIMSrubber being used and with the thermoplastic component. These curativesinclude sulfur, sulfur donors, metal oxides, resin systems,peroxide-based systems, hydrosilation curatives, containing platinum orperoxide catalysts, and the like, both with and without accelerators andco-agents. Such cure systems are well known in the art and literature ofvulcanization of elastomers.

The term “vulcanized” as used in the specification means that the rubbercomponent to be vulcanized has been cured to a state in which theelastomeric properties of the crosslinked rubber are similar to those ofthe rubber in its conventional vulcanized state, apart from thethermoplastic elastomer composition. The degree of cure can be describedin terms of gel content or, conversely, extractable components.Alternatively the degree of cure may be expressed in terms of crosslinkdensity. All of these descriptions are well known in the art, forexample in U.S. Pat. Nos. 5,100,947 and 5,157,081.

Depending upon the desired applications, the amount of rubber present inthe composition may range from 10 to 90 wt % of the total polymercontent of the composition. In most applications and particularly wherethe rubber component is dynamically vulcanized, the rubber componentwill constitute less than 70 wt %, more preferably less than 50 wt %,and most preferably 10-40 wt % of the total polymer content of thecomposition.

Melt processing temperatures of the TPE compositions will generallyrange from above the melting point of the highest melting polymerpresent in the TPE composition up to 300° C. Preferred processingtemperatures will range from 140° C. up to 260° C., more preferably from150° C. up to 240° C.

The hindered surface modified filler material may be combined with theBIMS rubber component at any mixing stage, i.e., when the BIMS andthermoplastic polymer are initially mixed or at the time that curativesor other additives are mixed where dynamically vulcanized compositionsare prepared. However, in a preferred embodiment, the filler material isfist compounded with the BIMS polymer at temperatures up to 300° C. toprovide a modified BIMS polymer of increased viscosity, and thismodified polymer then blended with the thermoplastic resin and any otheradditives present in the TPE composition.

The BIMS blend with the aminosilane offers improved viscosity propertiesthat allows for unexpected benefits in blends with thermoplastics. Dueto the flow activation energy and shear thinning characteristics ofisobutylene-based polymers, reductions in viscosity values of thesepolymer with an increase in temperature and shear rate are much strongerthan that of other polymers, especially of thermoplastics in general.Blending of thermoplastics with isobutylene-based polymers commonlyrequires high temperatures (>150° C.) and high shear rate (>100 l/s). Atthese temperatures and shear rates, viscosities of isobutylene-basedpolymers are significantly lower than that of desirable thermoplasticresins such as polyolefins. However, viscosity matching between theisobutylene-based polymer and their thermoplastic partner duringblending is essential in providing uniform mixing and fine blendmorphology that are critical in, for example, automotive components suchas innerliners, treads and sidewalls. Other uses include impactresistant automotive car parts such as interior and exterior trim, paneland bumper components.

Further, the BIMS/aminosilane blends are useful for innerliners (such asa DVA innerliner) and for treads. In the case for treads, treads composeof elastomer and elastomer blends (typically no thermoplastics).However, by using functionalized fillers, it has been found that thefiller partition into the BIMS phase can be controlled and, hence,beneficially raise the BIMS viscosity (during Banbury mixing ofelastomer compounds, BIMS viscosity erodes with mixing time and coulddrop well below that of, e.g., butadiene and other general purposerubbers due to the increase in temperature with mixing time). Thus, inone embodiment of the invention, the BIMS/aminosilane can form acomposition with a general purpose rubber such as butyl rubber,styrene-butadiene rubber, butadiene rubber, polyisoprene, halogenatedbutyl rubber, natural rubber, nitrile rubber, neoprene rubber, siliconrubber, polyurethane elastomers and other rubbers useful in making suchautomotive tire components as treads and sidewalls.

Other uses of the blends of the invention include low permeabilityelastic membranes (such as tire innerliners and protective clothingfabrics); closures for pharmaceutical and food containers; hot meltsealants; molded syringe plunger tips; and molded and extrudedautomotive components requiring low permeability just as hoses or hosecovers.

The blends of the present invention improve the viscosity matchingbetween thermoplastics and isobutylene-based polymer such as BIMS. Theviscosity values of the BIMS/aminosilane blends of the present inventionat 1000 l/s shear rate range from 200 to 500 Pa·s in one embodiment, andfrom 200 to 400 Pa·s in another embodiment, and from 200 to 350 Pa·s inyet another embodiment. The viscosity values of the BIMS/aminosilaneblends of the present invention at 1500 l/s shear rate range from 110 to400 Pa·s in one embodiment, and from 120 to 350 Pa·s in anotherembodiment, and from 130 to 250 Pa·s in yet another embodiment. Inblends with a thermoplastic, the dispersion size of the blendsBIMS/aminosilane (as measured by AFM) were from less than 1.8 μm(microns) in one embodiment, and from less than 1.5 μm in anotherembodiment, and from less than 1.2 μm in yet another embodiment, andfrom less than 1.0 μm in yet another embodiment, and from 0.1 to 1.8 μmin yet another embodiment, and from 0.3 to 1.6 μm in yet anotherembodiment.

One embodiment of the present invention includes a compositioncomprising a mixture of a halogenated copolymer of a C₄ to C₇isomonoolefin and a para-alkylstyrene; and silica or clay filler whichhas been contacted with at least one aminosilane. In another embodiment,the composition is dynamically vulcanized. The aminosilane may bedescribed in one embodiment as having at least one C₁ to C₄ alkoxy groupand at least one primary, secondary or tertiary amine group, the fillerpresent in the composition at a level of from 0.1 to 100 parts by weightper 100 parts by weight of the copolymer (phr).

In one embodiment, the copolymer is a brominated copolymer ofisobutylene and para-methylstyrene.

In another embodiment, the at least one aminosilane is described by theformula (H₂N—R_(4-n))—Si—(OR′)_(n) wherein R is C₁ to C₄ alkylene, R′ isC₁ to C₄ alkyl and n is a whole number ranging from 1 to 3.

In yet another embodiment, the filler contains 0.1 to 5 wt % of theaminosilane by weight of the filler-aminosilane blend.

In yet another embodiment, the filler material is silica.

In yet another embodiment, the filler material is clay.

In yet another embodiment, the viscosity value of the copolymer blendsat 1000 l/s shear rate range from 200 to 500 Pa·s.

In yet another embodiment, the viscosity value of the copolymer blendsat 1500 l/s shear rate range from 110 to 400 Pa·s.

Finally, the R_(B) value for the BIMS/aminosilane blend is from 20 to90% in yet another embodiment.

In yet another embodiment of the BIMS/aminosilane blend includes athermoplastic elastomer composition comprising a blend of at least onethermoplastic polymer and from 10 to 90 wt % of the BIMS/aminosilaneblend, based on the total polymer content of the composition. Thedispersion size of the blend is measured by AFM are from less than 1.8μm in a desirable embodiment, and the thermoplastic polymer is selectedfrom polyolefins, polyamides, polyimides, polyesters, polycarbonates,polysulfones, polylactones, polyacetals, acrylonitrile/butadiene/styrenecopolymer resins, polyphenylene oxides, ethylene-carbon monoxidecopolymers, polyphenylene sulfides, polystyrene, styrene/acrylonitrilecopolymer resins, styrene/maleic anhydride copolymer resins, aromaticpolyketones and mixtures thereof in another embodiment.

In yet another embodiment of the BIMS/aminosilane blend includes ageneral purpose rubber selected from butyl rubber, styrene-butadienerubber, butadiene rubber, polyisoprene, halogenated butyl rubber,natural rubber, nitrile rubber, neoprene rubber, silicon rubber,polyurethane elastomers, and blends thereof. The general purpose rubbermay be present in the same ranges as stated for the thermoplasticsabove.

The BIMS/aminosilane blend and the thermoplastic blend may be used tomake an automotive component such as a tire innerliner, tire tread, tiresidewall, or other impact resistant component of a car, truck, boat orother vehicle.

The following non-limiting examples are illustrative of the invention.

EXAMPLE 1

The rubbers and the amine-modified filler used in the examples aredescribed in Table 1. All viscosity values measured are at 220° C. usinga capillary rheometer.

Due to the flow activation and shear thinning of BIMS rubbers, theimpact of Mooney increase on viscosity value of BIMS rubber at 220° C.is significant only at low shear rates, ˜100 l/s, but non-existent athigher shear rates (as shown in Table 2). Since shear rates at 100 l/sand above are commonly employed in blending rubbers with plastics inmixers and extruders to deliver optimal mixing uniformity and dispersionsizes, other methods in raising the viscosity value of BIMS rubber arerequired, as shown in Table 2.

A two-roll mill blended the Burgess 2211 clays into BIMS 89-4. Claycontents used were 5 phr (part per hundred of polymer) and 50 phr. Asshown in Table 3, by adding more than 5 phr of Burgess 2211 clay,viscosity values at all shear rates of BIMS at 220° C. could be raised.

A Brabender blended the Aerosil R504 silica into BIMS 89-4 at 150° C.and 60 RPM. Silica contents used were 10 phr and 25 phr. As shown inTable 4, viscosity values at all shear rates of BIMS at 220° C. could beraised by adding aminosilane treated silica. Due to the small sizes ofthese silica particles, viscosity enhancement in BIMS is moresignificant by using the silica instead of the clay.

EXAMPLE 2

Polypropylene PP4292 from ExxonMobil Chemical was selected as thethermoplastic blend component with BIMS. PP4292 is ahigh-viscosity-grade isotactic polypropylene with MFR of 1.5. A 60/40 byweight blend of PP4292 with BIMS (EXXPRO™ 89-4) and BIMS containingaminosilane treated silica (25 phr of Aerosil R504) were prepared usinga Brabender mixer at 80 RPM and 220° C. Morphologies of resulting blendswere examined by AFM followed by image processing to determine thedispersion sizes. As shown in Table 5, finer dispersions were obtainedin blends with enhanced-viscosity BIMS.

One of the methods in achieving the reduction in dispersion size is byviscosity matching. By raising the viscosity value of BIMS through theaddition of fillers such as the aminosilane, viscosity of filled BIMS isbrought up to that of thermoplastics such as polypropylene. The usage offillers is one method of raising the viscosity of elastomer in thepresent invention. However, the non-functionalized fillers, withoutspecific functionality to react with BIMS, such as carbon black andsilica, would thermodynamically and kinetically partition and distributeamong the thermoplastic and BIMS phases and, thus, adversely affect theintent in raising the viscosity of the rubber phase. The advantages ofthe present invention are thus achieved with the aminosilane fillers.The reduction in dispersion size is due to the viscosity matching.

This is useful in thermoplastic blends with BIMS, vulcanized orunvulcanized, for thermoplastic elastomer applications in areas ofimpact modified plastics and low permeability thermoplastic elastomer.

EXAMPLE 3

A further example of an enhanced viscosity blend of a BIMS polymer andan aminosilane is described with reference to Table 6. Mixing of thesilica filled stocks (10 and 30 phr of Aerosil R504) based on EXXPRO™90-10 was carried out in a Brabender mixer (started at 25° C. and 40rpm, mixed for 8 min; changed to 60 rpm, mixed for 1 min and dischargedat 93° C.), followed by sheeting on a two-roll mill to provide a highlevel of silica dispersion. No additives other than the filler wereadded in these BIMS/aminosilane blends.

Bound rubber is the amount of rubber unextractable from the unvulcanizedpolymer/filler blend after immersion in a solvent such as cyclohexane(in which the rubber is completely soluble) at room temperature for aduration of one week. Bound rubber (R_(B)) was then calculated accordingto the following equation:R _(B)=[{Wt. of sample after immersion−Wt. of filler insample}×100%]÷(Wt. of polymer is sample)

A stainless steel thimble was used to contain the polymer/filler blendfor solvent extraction. The R_(B) values in Table 6 indicate that BIMSremains associated with the filler material.

It is expected that, in one embodiment of the invention, the R_(B) valuefor the BIMS/aminosilane blends of the invention will range from 20 to90% in one embodiment, and from 22 to 80% in another embodiment, andfrom 25 to 60% in yet another embodiment, and from 26 to 45% in yetanother embodiment, a desirable range of R_(B) values including anycombination of any upper R_(B) limit with any lower R_(B) limitdescribed herein.

Polymers and polymer/filler blends were molded between two pieces ofTeflon-coated aluminum foil at 150° C. for 25 min. Molded samples weredie-cut into micro-dumbbell specimens as per ASTM D1708 for tensilestress-strain measurements, which were performed at a crosshead speed of2 in/min and at room temperature using an Instron tester. The stress wascalculated based on the undeformed cross-sectional area of the tensilespecimen. The results of the measurements are in Table 6.

The large increases in bound rubber, yield stress and tensile strengthwith the incorporation of amine treated silica filler suggests a stronginteraction between the polymer and the filler. This strongpolymer/filler interaction will result in an enhanced viscosity, asshown in the last column of Table 6. The peak viscosity was estimatedfrom the yield stress and the strain rate in the tensile elongationprocess.

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to many differentvariations not illustrated herein. For these reasons, then, referenceshould be made solely to the appended claims for purposes of determiningthe scope of the present invention. Further, certain features of thepresent invention are described in terms of a set of numerical upperlimits and a set of numerical lower limits. It should be appreciatedthat ranges formed by any combination of these limits are within thescope of the invention unless otherwise indicated.

All priority documents are herein fully incorporated by reference forall jurisdictions in which such incorporation is permitted. Further, alldocuments cited herein, including testing procedures, are herein fullyincorporated by reference for all jurisdictions in which suchincorporation is permitted.

TABLE 1 Materials Used Designation Description Material BIMS 89-4 BIMSrubber, 45 ML* EXXPRO ™ 89-4, 0.75 mol % Br ExxonMobil Chemical 5 wt %PMS BIMS 91-11 BIMS rubber, 65 ML EXXPRO ™ 91-11, 1.1 mol % BrExxonMobil Chemical 5 wt % PMS BIMS 90-10 BIMS rubber, 45 ML EXXPRO ™91-11, 1.2 mol % Br ExxonMobil Chemical 7.5 wt % PMS 2211 Aminosilanetreated clays, Burgess 2211, Burgess particle size is 1.4 μm PigmentCompany R504 Aminosilane treated silica, Aerosil R504, Degussa particlesize is 12 nm Company *ML is Mooney viscosity measured at 125° C. and 1s⁻¹, error of ± 5 units.

TABLE 2 Viscosity values of BIMS with low and high Mooney values. ShearRate (l/s) Viscosity* of BIMS 89-4 Viscosity of BIMS 91-11 100 1274 1468500 378 383 1000 200 197 1500 136 133 *Measured at 220° C. using acapillary rheometer. Values are in Pa-s.

TABLE 3 Viscosity values of BIMS 89-4 at 220° C. in Pa-s filled withamine-modified clays. BIMS with 50 phr Shear Rate (l/s) BIMS 89-4 BIMSwith 5 phr 2211 2211 100 1274 1368 1806 500 378 385 484 1000 200 202 2531500 136 137 171 5000 42 42 52 20000 11 11 13

TABLE 4 Viscosity values of BIMS 89-4 at 220° C. in Pa-s filled withamine-modified silica. BIMS with 10 phr BIMS with 25 phr Shear Rate(l/s) BIMS 89-4 R504 R504 100 1274 1545 2266 500 378 447 619 1000 200236 314 1500 136 161 216 5000 42 50 67 20000 11 13 18

TABLE 5 Blends of Polypropylene and Enhanced viscosity BIMS BlendsDispersion size (micron)* PP4292/BIMS (control) 2.08 PP4292/aminosilanetreated silica BIMS 0.91 *number average equivalent diameter of the BIMSdispersions.

TABLE 6 Stress Strain measurements of Example 3 samples Peak YieldTensile Viscosity, Stress, Strength, Breaking Pa · s composition R_(B),% MPa MPa Strain, % (estimated) EXXPRO ™ 0 0.26 0.0006 2050 31.2 × 10⁶90-10 EXXPRO ™ 32 0.34 0.01 650 40.8 × 10⁶ 90-10, 10 phr R504 EXXPRO ™46 0.78 0.02 650 93.6 × 10⁶ 90-10, 30 phr R504

1. A thermoplastic elastomer composition comprising a blend of: a) atleast one thermoplastic polymer; and b) dispersed therein a mixture offrom 10 to 90 wt % based on the total polymer content of the compositionof a halogenated copolymer of a C₄ to C₇ isomonoolefin and apara-alkylstyrene, and silica or clay filler which has been contactedwith at least one aminosilane having at least one C₁ to C₄ alkoxy groupand at least one primary, secondary or tertiary amine group, the fillerpresent in the composition at a level of from 0.1 to 100 parts by weightper 100 parts by weight of the copolymer; said composition furthercomprising a general purpose rubber selected from the group consistingof butyl rubber, styrene-butadiene rubber, butadiene rubber,polyisoprene, halogenated butyl rubber, natural rubber, nitrile rubber,neoprene rubber, silicon rubber, polyurethane elastomers, and blendsthereof.
 2. An automotive component made from the composition ofclaim
 1. 3. A process for improving the mixing of a thermoplasticpolymer and a halogenated copolymer of a C₄ to C₇ isomonoolefin and apara-alkylstyrene comprising: melt mixing a halogenated copolymer of aC₄ to C₇ isomonoolefin and a para-alkylstyrene with 0.1 to 100 partsweight of a silica or clay filler which has been contacted at least oneaminosilane having at least one C₁ to C₄ alkoxy group and at least oneprimary, secondary or tertiary amine group, the parts by weight based on100 parts by weight of the copolymer, to form a copolymer blend;blending at least one thermoplastic polymer with the copolymer blend todynamically vulcanize the copolymer blend and form a dispersion of thevulcanizate in the thermoplastic polymer; and blending at least one ofbutyl rubber, styrene-butadiene rubber, butadiene rubber, polyisoprene,halogenated butyl rubber, natural rubber, nitrile rubber, neoprenerubber, silicon rubber, polyurethane elastomers, and blends thereof. 4.The mixture of thermoplastic polymer and halogenated copolymer made fromthe process of claim
 3. 5. A process for preparing a blend compositionof (a) at least one thermoplastic polymer and from 10 to 90 wt % basedon the total polymer content of (b) a dynamically vulcanized compositioncomprising: i) a halogenated copolymer of a C₄ to C₇ isomonoolefin and apara-alkylstyrene; and ii) silica or clay filler which has beencontacted with at least one aminosilane having at least one C₁ to C₄alkoxy group and at least one primary, secondary or tertiary aminegroup, the filler present in the composition at a level of from 0.1 to100 parts by weight per 100 parts by weight of the copolymer; comprisingmixing (a) with a curable blend of (i) and (ii) to obtain a blendcomprising dynamically vulcanized (b) and the thermoplastic polymer; andfurther comprising blending a general purpose rubber selected from thegroup consisting of butyl rubber, styrene-butadiene rubber, butadienerubber, polyisoprene, halogenated butyl rubber, natural rubber, nitrilerubber, neoprene rubber, silicon rubber, polyurethane elastomers, andblends thereof.
 6. The process of claim 5, wherein a dispersion size ofthe vulcanized (b) in the blend as measured by AFM is from less than 1.8μm.
 7. The blend composition produced in accordance with the process ofclaim
 6. 8. The process of claim 5, wherein the thermoplastic polymer isselected from the group consisting of polyolefins, polyamides,polyimides, polyesters, polycarbonates, polysulfones, polylactones,polyacetals, acrylonitrile/butadiene/styrene copolymer resins,polyphenylene oxides, ethylene-carbon monoxide copolymers, polyphenylenesulfides, polystyrene, styrene/acrylonitrile copolymer resins,styrene/maleic anhydride copolymer resins, aromatic polyketones andmixtures thereof.
 9. The process of claim 5, wherein a R_(B) value forthe dynamically vulcanized (b) is from 20 to 90%.
 10. The process ofclaim 3, wherein a dispersion size of the copolymer blend as measured byAFM is from less than 1.8 μm.
 11. The process of claim 3, wherein thethermoplastic polymer is selected from the group consisting ofpolyolefins, polyamides, polyimides, polyesters, polycarbonates,polysulfones, polylactones, polyacetals, acrylonitrile/butadiene/styrenecopolymer resins, polyphenylene oxides, ethylene-carbon monoxidecopolymers, polyphenylene sulfides, polystyrene, styrene/acrylonitrilecopolymer resins, styrene/maleic anhydride copolymer resins, aromaticpolyketones and mixtures thereof.
 12. The process of claim 3, whereinthe thermoplastic polymer is a polypropylene homopolymer, impactcopolymer, or copolymer.
 13. The process of claim 3, wherein a R_(B)value for the vulcanizate is from 20 to 90%.
 14. The composition ofclaim 1, wherein a dispersion size of (b) in the blend as measured byAFM is from less than 1.8 μm.
 15. The composition of claim 1, whereinthe thermoplastic polymer is selected from the group consisting ofpolyolefins, polyamides, polyimides, polyesters, polycarbonates,polysulfones, polylactones, polyacetals, acrylonitrile/butadiene/styrenecopolymer resins, polyphenylene oxides, ethylene-carbon monoxidecopolymers, polyphenylene sulfides, polystyrene, styrene/acrylonitrilecopolymer resins, styrene/maleic anhydride copolymer resins, aromaticpolyketones and mixtures thereof.
 16. A process for improving the mixingof a thermoplastic polymer and a halogenated copolymer of a C₄ to C₇isomonoolefin and a para-alkylstyrene comprising: contacting a silica orclay filler with at least one aminosilane having at least one C₁ to C₄alkoxy group and at least one primary, secondary or tertiary aminegroup; melt mixing a halogenated copolymer of a C₄ to C₇ isomonoolefinand a para-alkylstyrene with 0.1 to 100 parts by weight of theaminosilane-contacted silica or clay filler, the parts by weight basedon 100 parts by weight of the copolymer; blending at least onethermoplastic polymer with the copolymer mixture; and blending at leastone of butyl rubber, styrene-butadiene rubber, butadiene rubber,polyisoprene, halogenated butyl rubber, natural rubber, nitrile rubber,neoprene rubber, silicon rubber, polyurethane elastomers, and blendsthereof.
 17. An automotive component made from the mixture of claim 4.18. An automotive component made from the composition of claim
 7. 19.The process of claim 3 further comprising making an automotive componentfrom the thermoplastic polymer-halogenated copolymer mixture.
 20. Theprocess of claim 5 further comprising making an automotive componentfrom the blend composition.
 21. A process for preparing a blendcomposition of at least one thermoplastic polymer and from 10 to 90 wt %based on the total polymer content of an elastomeric composition,comprising: preparing a vulcanizable composite comprising: i) ahalogenated copolymer of a C₄ to C₇ isomonoolefin and apara-alkylstyrene; and iii) silica or clay filler which has beencontacted with at least one aminosilane having at least one C₁ to C₄alkoxy group and at least one primary, secondary or tertiary aminegroup, the filler present in the composition at a level of from 0.1 to100 parts by weight per 100 parts by weight of the copolymer; and mixingthe at least one thermoplastic polymer with the composite at vulcanizingconditions to obtain a blend comprising the dynamically vulcanizedcomposite dispersed in the thermoplastic polymer.
 22. The process ofclaim 21, wherein a dispersion size of the dynamically vulcanizedcomposite as measured by AFM is from less than 1.8 μm.
 23. The processof claim 21, wherein the thermoplastic polymer is selected from thegroup consisting of polyolefins, polyamides, polyimides, polyesters,polycarbonates, polysulfones, polylactones, polyacetals,acrylonitrile/butadiene/styrene copolymer resins, polyphenylene oxides,ethylene-carbon monoxide copolymers, polyphenylene sulfides,polystyrene, styrene/acrylonitrile copolymer resins, styrene/maleicanhydride copolymer resins, aromatic polyketones and mixtures thereof.24. The process of claim 21, wherein a R_(B) value for the dynamicallyvulcanized composite is from 20 to 90%.
 25. A dynamically vulcanizedcomposition comprising: a blend of: a) at least one thermoplasticpolymer, and b) dispersed therein from 10 to 90 wt. % based on the totalpolymer content of the composition of a blend comprising a halogenatedcopolymer of a C₄ to C₇ isomonoolefin and a para-alkylstyrene vulcanizedin a composite mixture with silica or clay filler which has beencontacted with at least one aminosilane having at least one C₁ to C₄alkoxy group and at least one primary, secondary or tertiary aminegroup, the filler present in the composition at a level of from 0.1 to100 parts by weight per 100 parts by weight of the copolymer.
 26. Thecomposition of claim 25, wherein the copolymer is a brominated copolymerof isobutylene and para-methylstyrene.
 27. The composition of claim 25,wherein the at least one aminosilane is described by the formula(H₂N—R_(4-n))—Si—OR′)_(n) wherein R is C₁ to C₄ alkylene, R′ is C₁ to C₄alkyl and n is a whole number ranging from 1 to
 3. 28. The compositionof claim 25, wherein the aminosilane comprisestriethoxypropylaminosilane.
 29. The composition of claim 25, wherein thefiller contains 0.1 to 5 wt % of the aminosilane by weight of thefiller.
 30. The composition of claim 25, wherein the filler comprisessilica.
 31. The composition of claim 25, wherein the filler comprisesclay.
 32. The composition of claim 25, wherein a viscosity value of the(uncured) composite mixture at 1000 l/s shear rate range from 200 to 500Pa·s.
 33. The composition of claim 25, wherein a viscosity value of the(uncured) composite mixture at 1500 l/s shear rate range from 110 to 400Pa·s.